Manufacturing-friendly plastic surface destroys viruses on contact

Researchers at RMIT have developed a plastic film that tears apart viruses on contact, offering a promising new way to keep high-touch surfaces such as smartphones and hospital equipment from spreading disease.

The innovation is not only effective at killing viruses, but also far more practical and scalable than earlier metal and silicon‑based antiviral surfaces. The flexible acrylic surface is textured with ultra‑fine structures called nanopillars that grab and stretch the outer shell of the virus so much that it ruptures, killing the virus through mechanical force rather than chemical disinfectants.

Unlike earlier studies on antiviral coatings, this research shows stretching rather than skewering viruses is a more effective kill.

In lab tests with the human parainfluenza virus 3 (hPIV-3) — which causes bronchiolitis and pneumonia — about 94% of the virus particles were either ripped apart or damaged to the point where they could no longer replicate to cause infection within one hour of contact with the surface.

Study lead author and PhD candidate Samson Mah, from Australia’s RMIT University, said the team used cheap, flexible plastic that can be made in big factory rolls, like cling wrap.

“As nanofabrication tools get better, our results give a clearer guide to which nanopatterns work best to kill viruses,” he said. “We could one day have surfaces like phone screens, keyboards and hospital tables covered with this film, killing viruses on contact without using harsh chemicals.

“Our mould can be adapted to roll‑to‑roll manufacturing, meaning antiviral plastic films could be produced at scale with existing factory equipment.”

Mah said the research revealed how the distance between the nanopillars matters far more than their height.

“By tweaking the spacing and height of the nanopillars, we discovered how tightly they are packed together is far more important than how tall they are for breaking viruses apart,” he said. “When the nanopillars are closer together, more of them can press on the same virus at once, stretching its outer shell past breaking point.”

While early experiments on rigid substrates such as nanospike silicon showed viruses could be physically disrupted, this study showed the surfaces textured with not only spiky-like nanofeatures, but also with blunt nanopillars can efficiently kill viruses.

Microscope image of a virus cell being ruptured by the nanotextured surface. Credit: RMIT

This new research shows the same virus‑killing action on flexible plastic and proposes a simple design rule: the closer together the nanofeatures such as spikes or nanopillars are, the better they work. The strongest effect came from densely packed nanopillars with about 60 nm between them, while widening the gaps to 100 nm reduced the antiviral power and 200 nm effectively switched it off.

So far, the work has focused on hPIV‑3, an enveloped virus with a fatty outer membrane; the team now plans to test smaller and non‑enveloped viruses to see how broadly the nanotextured surface works.

An enveloped virus has a fragile fatty membrane around it that can be more easily disrupted by nanopillars, while a non-enveloped virus lacks this outer layer, making it harder to kill.

More research is also needed to study the texturing’s effectiveness on curved surfaces, which affect the nanopillars’ spacing.

The research paper ‘Designing Scalable Mechano-Virucidal Nanostructured Acrylic Surfaces for Enhanced Viral Inactivation’, is published in Advanced Science.

Top image: (L–R) Associate Professor Natalie Borg, Dr Denver Linklater, Distinguished Professor Elena Ivanova and Samson Mah. Credit: RMIT